1. Field of the Invention
The present invention relates to a recording medium and a process for producing the same.
2. Description of the Related Art
In the field of recent commercial printing, an on-demand photograph collection in which chosen photographs or photographs accompanied with characters are collected, namely, a photo book or a photo album, is recently bound as a booklet. In such a booklet, there is a demand for such a usage as arranging images on both surfaces of one sheet. Accordingly, a recording medium applicable to printing on both surfaces, in particular, an ink jet recording medium having high glossiness on both surfaces has been demanded. In order to attain a highly glossy ink jet recorded surface, it is effective to use a smooth base.
Japanese Patent Application Laid-Open No. 2004-284146 discloses an ink jet recording medium obtained by coating both surfaces of a paper sheet with a polyolefin resin and further providing an undercoating layer mainly made of a hydrophilic polymer and a porous ink-absorbing layer in this order on the polyolefin resin. The front surface of the polyolefin resin coating layer having the porous ink-absorbing layer thereon is subjected to a fine roughening treatment, and the front surface of the undercoating layer has a 75° specular glossiness of 30% or more and 80% or less.
Japanese Patent Application Laid-Open No. 2004-284148 discloses an ink jet recording medium including a polyolefin resin coating layer, an undercoating layer containing a hydrophilic polymer and a porous ink-absorbing layer all formed on both surfaces of a paper base. In the front surface of the polyolefin resin coating layer having the porous ink-absorbing layer thereon, the filtered maximum waviness and central line average roughness Ra are controlled. Specifically, the filtered maximum waviness determined according to JIS B 0610 (a low band cut-off value of 8 mm, a high band cut-off value of 0.8 mm and a reference length of 80 mm) is controlled to be 1 μm or more and 3 μm or less. Besides, the central line average roughness Ra determined according to JIS B 0601 (a reference length of 2.5 mm and a cut-off value of 0.8 mm) is controlled to be 0.1 μm or more and 0.5 μm or less.
On the other hand, for improving the productivity, a recording medium is generally produced into a long sheet shape and then the sheet-shaped recording medium is cut into a desired size to obtain a product. Therefore, in order that the production can be performed in a space-saving manner, the production process includes a step of winding the sheet-shaped recording medium into a roll, and various methods have been proposed for stabilizing this process.
Japanese Patent Application Laid-Open No. 2005-246962 discloses a method for winding, into a roll, a long web of an ink jet recording medium including a raw paper having both surfaces coated with a polyolefin resin, and an ink-receiving layer that is formed on each polyolefin resin coating and contains an inorganic particle and a hydrophilic binder. In this method, when the winding tension upon winding of the recording medium is T (Kgf/m) and the thickness of the ink-receiving layer is t (m), the recording medium is wound up with the value A that is expressed as A=T×t×1000 being within the range of 0.5 or more and 3 or less.